package com.ztt.utils;

import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;

public class ImageUtils {

	/**
	 * 实现图像的缩放 直接根据高度
	 * 
	 * @param source
	 * @param targetW
	 * @return
	 */
	private static BufferedImage resize(BufferedImage source, int targetW) {
		// targetW宽
		int type = source.getType();
		BufferedImage target = null;
		double sx = (double) targetW / source.getWidth();
	    int height= (int)((int)source.getHeight()*sx);
		if (type == BufferedImage.TYPE_CUSTOM) { // handmade
			ColorModel cm = source.getColorModel();
			WritableRaster raster = cm.createCompatibleWritableRaster(targetW,
					height);
			boolean alphaPremultiplied = cm.isAlphaPremultiplied();
			target = new BufferedImage(cm, raster, alphaPremultiplied, null);
		} else
			target = new BufferedImage(targetW, height, type);
		Graphics2D g = target.createGraphics();
		// smoother than exlax:
		g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
				RenderingHints.VALUE_INTERPOLATION_BICUBIC);
		g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sx));
		g.dispose();
		return target;
	}

	/**
	 * 实现图像的等比缩放
	 * 
	 * @param source
	 * @param targetW
	 * @param targetH
	 * @return
	 */
	private static BufferedImage resize(BufferedImage source, int targetW,
			int targetH) {
		// targetW，targetH分别表示目标长和宽
		int type = source.getType();
		BufferedImage target = null;
		double sx = (double) targetW / source.getWidth();
		double sy = (double) targetH / source.getHeight();
		// 这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放
		// 则将下面的if else语句注释即可
		if (sx <= sy) {
			sx = sy;
			//targetW = (int) (sx * source.getWidth());
		} else {
			sy = sx;
			//targetH = (int) (sy * source.getHeight());
		}
		if (type == BufferedImage.TYPE_CUSTOM) { // handmade
			ColorModel cm = source.getColorModel();
			WritableRaster raster = cm.createCompatibleWritableRaster(targetW,
					targetH);
			boolean alphaPremultiplied = cm.isAlphaPremultiplied();
			target = new BufferedImage(cm, raster, alphaPremultiplied, null);
		} else
			target = new BufferedImage(targetW, targetH, type);
		Graphics2D g = target.createGraphics();
		// smoother than exlax:
		g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
				RenderingHints.VALUE_INTERPOLATION_BICUBIC);
		g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
		g.dispose();
		return target;
	}

	/**
	 * 实现图像的等比缩放和缩放后的截取
	 * 
	 * @param inFilePath
	 *            要截取文件的路径
	 * @param outFilePath
	 *            截取后输出的路径
	 * @param width
	 *            要截取宽度
	 * @param hight
	 *            要截取的高度
	 * @param proportion
	 *            当proportion为true的时候 根据宽和高进行处理图片，如果为false的时候，直接等比压缩，省略到高度
	 * @throws Exception
	 */

	public static void saveImageAsJpg(String inFilePath, String outFilePath,
			int width, int hight, boolean proportion) throws Exception {
		File file = new File(inFilePath);
		InputStream in = new FileInputStream(file);
		File saveFile = new File(outFilePath);
		BufferedImage srcImage = ImageIO.read(in);
		if (proportion) {
			if (width > 0 || hight > 0) {
				// 原图的大小
				int sw = srcImage.getWidth();
				int sh = srcImage.getHeight();
				// 如果原图像的大小小于要缩放的图像大小，直接将要缩放的图像复制过去
				if (sw > width && sh > hight) {
					srcImage = resize(srcImage, width, hight);
				} else {
					String fileName = saveFile.getName();
					String formatName = fileName.substring(fileName
							.lastIndexOf('.') + 1);
					ImageIO.write(srcImage, formatName, saveFile);
					return;
				}
			}
			// 缩放后的图像的宽和高
			int w = srcImage.getWidth();
			int h = srcImage.getHeight();

			// 如果缩放后的图像和要求的图像宽度一样，就对缩放的图像的高度进行截取
			if (w == width) {
				// 计算X轴坐标
				int x = 0;
				int y = h / 2 - hight / 2;
				saveSubImage(srcImage, new Rectangle(x, y, width, hight),
						saveFile);
			}
			// 否则如果是缩放后的图像的高度和要求的图像高度一样，就对缩放后的图像的宽度进行截取
			else if (h == hight) {
				// 计算X轴坐标
				int x = w / 2 - width / 2;
				int y = 0;
				saveSubImage(srcImage, new Rectangle(x, y, width, hight),
						saveFile);
			}
		} else {
			// 需要根据高度进行等比压缩，省略掉图片的高度
			if (width > 0) {
				int sw = srcImage.getWidth(); // 原图的宽度
				// 如果原图像的大小小于要缩放的图像大小，直接将要缩放的图像复制过去
				if (sw > width) {
					srcImage = resize(srcImage, width);
				} else {
					String fileName = saveFile.getName();
					String formatName = fileName.substring(fileName
							.lastIndexOf('.') + 1);
					ImageIO.write(srcImage, formatName, saveFile);
					return;
				}
			}
			// 缩放后的图像的宽和高
			int w = srcImage.getWidth();
		    int h = srcImage.getHeight();
		    saveSubImage(srcImage, new Rectangle(0, 0, w, h),
					saveFile);
		}
		in.close();
	}

	/**
	 * 实现缩放后的截图
	 * 
	 * @param image
	 *            缩放后的图像
	 * @param subImageBounds
	 *            要截取的子图的范围
	 * @param subImageFile
	 *            要保存的文件
	 * @throws IOException
	 */
	private static void saveSubImage(BufferedImage image,
			Rectangle subImageBounds, File subImageFile) throws IOException {
		if (subImageBounds.x < 0 || subImageBounds.y < 0
				|| subImageBounds.width - subImageBounds.x > image.getWidth()
				|| subImageBounds.height - subImageBounds.y > image.getHeight()) {
			System.out.println("Bad   subimage   bounds");
			return;
		}
		BufferedImage subImage = image.getSubimage(subImageBounds.x,
				subImageBounds.y, subImageBounds.width, subImageBounds.height);
		String fileName = subImageFile.getName();
		String formatName = fileName.substring(fileName.lastIndexOf('.') + 1);
		ImageIO.write(subImage, formatName, subImageFile);
	}

}
